The present invention relates generally to methods of preventing communication between adjacent wells. In particular, the present invention relates to methods of preventing or minimizing communication between adjacent wells using conformance chemicals, diverting agents, or a combination thereof.
Wellbores drilled through subsurface rock formations to extract oil and gas may be treated by pumping various types of fluids into the formations. Fluid pumping treatments include, for example, hydraulic fracturing, wherein fluid is pumped into the formation at pressure that exceeds the fracture pressure of the formations. The fractures thus opened may be held open by pumping of proppant that supports the fracture structurally after the fluid pressure on the formation is relieved. Other fluid treatments may include, for example, pumping acid into the wellbore to dissolve certain minerals present in the pore spaces of the formations that reduce the formation permeability.
In certain land drilling locations, a number of wells are drilled from the same surface location, referred to as a “pad.” The wells are drilled directionally to access oil reservoirs that extend horizontally from the pad.
Pad drilling is the practice of drilling multiple wellbores from a single surface location. Prior to the advent of pad drilling, an operator would drill a single well, disassemble the drilling rig, move it to a new location, and then repeat the process. Through pad drilling, 4, 10, 20 or more wells can be drilled from the pad. Doing so saves time and money that would be spent packing and moving the rig and preparing a new drilling site. It also means a smaller impact on the area landscape.
In current hydraulic fracturing operations, large amounts of fluid and proppants are pumped into a reservoir to unlock the vast amount of trapped oil and gas in a pad with multiple wellbores. In dealing with multiple wellbores, close proximity of fractures in adjacent wells is necessary to achieve economical production of hydrocarbons. Due to close spacing, however, communication in a multi-fractured well pad can cause many challenges, such as loss of production of an offset well and excessive consumption of fracturing fluid and proppant. Moreover, old wells can lose production after stimulating nearby wells, or there may be ineffective stimulation of a new well due to communication between the old well and the new well.
Thus, there is a continuing need for improved methods and compositions for preventing or minimizing “well bashing,” or the detrimental communication between two or more adjacent wells. In particular, there is a need to block or otherwise seal the fractures of a first well that are most likely to communicate with a second, adjacent well.